Huge banners calling on Egyptians to support constitutional amendments that would keep President Abdul Fattah al-Sisi in power until 2030.
Egyptians began voting on Saturday in a three-day referendum on the proposed changes, a few days after they were approved by a sweeping majority inside parliament.
"Say yes to stability and security," reads one banner in central Cairo. The new amendments will extend the presidential term from four to six years, and the president can only be re-elected once.
But Mr Sisi is being given special treatment.
Not only will his current term be extended to six years, but he will be allowed to run for a third term as an exception.
The military-backed president, who took office in 2014, was originally meant to leave in 2022 after his second term expires.